Table 1. Maternal characteristics and pregnancy outcome in relation to maternal age.
| Maternal age 20–29 years | Maternal age 30–34 years | Maternal age 35–39 years | Maternal age 40+ years | |
| Maternal Characteristic | 122,307 (54.2) | 62,371 (27.6) | 33,966 (15.1) | 7,066 (3.1) |
| Deprivation score* | ||||
| First group: most deprived | 34,352 (28.1) | 10,786 (17.3) | 5,218 (15.4) | 1,113 (15.7) |
| Second group | 32,115 (26.3) | 11,513 (18.5) | 5,737 (16.9) | 1,205 (17.1) |
| Third group | 26,910 (22.0) | 15,286 (24.5) | 8,223 (24.2) | 1,738 (24.6) |
| Fourth group: least deprived | 18,354 (15.0) | 19,323 (31.0) | 11,721 (34.5) | 2,350 (33.3) |
| Fifth group: missing postcodes | 10,576 (8.6) | 5,463 (8.8) | 3,067 (9.0) | 660 (9.3) |
| Ethnic origin | ||||
| White | 80,419 (65.8) | 43,137 (69.2) | 24,473 (72.1) | 4,959 (70.2) |
| Black | 3,647 (3.0) | 1,844 (3.0) | 975 (2.9) | 267 (3.8) |
| Indian | 3,947 (3.2) | 1,865 (3.0) | 652 (1.9) | 86 (1.2) |
| Asian [ Bangladeshi and Pakistani] | 14,372 (11.7) | 4,689 (7.5) | 1,825 (5.4) | 322 (4.6) |
| Chinese | 582 (0.5) | 340 (0.5) | 172 (0.5) | 51 (0.7) |
| Other | 19,340 (15.8) | 10,496 (16.8) | 5,869 (17.3) | 1,381 (19.5) |
| Parity | ||||
| Primiparous | 50,534 (41.3) | 19,334 (31.0) | 8,077 (23.8) | 1,558 (22.1) |
| Multiparous | 71,773 (58.7) | 43,037 (69.0) | 25,889 (76.2) | 5,508 (77.9) |
| Infant sex | ||||
| Male | 62,823 (51.4) | 32,137 (51.5) | 17,356 (51.1) | 3,563 (50.4) |
| Female | 59,484 (48.6) | 30,234 (48.5) | 16,610 (48.9) | 3,503 (49.6) |
| BMI | ||||
| Underweight | 3,262 (2.7) | 717 (1.1) | 278 (0.8) | 63 (0.9) |
| Normal | 44,879 (36.7) | 21,043 (33.7) | 10,577 (31.1) | 1,998 (28.3) |
| Overweight | 23,908 (19.5) | 13,857 (22.2) | 7,884 (23.2) | 1,643 (23.2) |
| Obese | 14,036 (1.48) | 7,720 (12.4) | 4,525 (13.3) | 952 (13.5) |
| Morbidly obese | 1,787 (1.5) | 1,001 (1.6) | 566 (1.7) | 130 (1.8) |
| Missing BMI | 34,435 (28.1) | 18,033 (28.9) | 10,136 (29.8) | 2,280 (32.3) |
| Smoking (2007–08) | ||||
| No | 38, 515 (72.9) | 21,265 (82.4) | 12,708 (82.7) | 2,849 (80.8) |
| Yes | 11,334 (21.5) | 2,985 (11.6) | 1,732 (11.3) | 444 (12.6) |
| Unknown (in 2007–08) | 2,949(5.6) | 1,548(6.0) | 931(6.1) | 231(6.6) |
| Stillbirth | 554 (0.4) | 313 (0.5) | 190 (0.6) | 52 (0.7) |
| Neonatal death | 264 (0.22) | 144 (0.23) | 77 (0.23) | 16 (0.23) |
| Preterm delivery | 7,041 (6.1) | 3,582 (6.1) | 2,223(6.9) | 464 (6.9) |
| Very preterm delivery | 1,528 (1.4) | 751 (1.3) | 475 (1.6) | 100 (1.6) |
| All Caesarean sections | 22,424 (18.4) | 15,573 (25.1) | 9,983 (29.6) | 2,397 (34.2) |
| Emergency only | 11,839 (9.7) | 7,317 (11.8) | 4,228 (12.5) | 1,016 (14.5) |
| Elective only | 10,585 (8.7) | 8,256 (13.3) | 5,755 (17.0) | 1,381 (19.7) |
| ESGA | 3,470 (3.2) | 1,348 (2.4) | 744 (2.4) | 169 (2.7) |
| VSGA | 5,846 (5.3) | 2,286 (4.0) | 1,235 (3.9) | 281 (4.4) |
| SGA | 12,012 (10.3) | 4,741 (8.0) | 2,444 (7.6) | 564(8.4) |
| LGA | 10,186 (8.8) | 6,995 (11.8) | 4,273 (13.3) | 906 (13.5) |
| VLGA | 4,999 (4.5) | 3,567 (6.4) | 2,209 (7.3) | 496 (7.9) |
| ELGA | 2,952 (2.7) | 2,162 (4.0) | 1,359 (4.6) | 298 (4.9) |
| Macrosomia | 1,752 (1.4) | 1,227 (2.0) | 738 (2.2) | 162 (2.3) |
Data refers to N (%). *Birth weight ESGA (Extremely small-for-gestational age, <3rd percentile); VSGA (Very small-for-gestational age, <5th percentile); SGA (Small-for-gestational age, <10th percentile); LGA (Large-for-gestational age, >90th percentile); VLGA (Very-large-for-gestational age, >95th percentile); ELGA (Extremely-large-for-gestational-age, >97th percentile).